One of the first steps you take when you are estimating your gardening schedule is find your USDA Zone info. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

The USDA zone info for Harrisburg should be used to figure out when it's the best time to plant watermelon.

Planting Calendar for Watermelon

Frost tolerance for watermelon:	Not tolerant of frost.
When to plant:	After the last frost when the weather gets warmer.

Since watermelon do not do well in cold weather it is necessary to wait until after the last frost has passed before you can plant them.

The earliest that you can plant watermelon in Harrisburg is April. However, you really should wait until May if you don't want to take any chances.

The last month that you can plant watermelon and expect a good harvest is probably August. Any later than that and your watermelon may not have a chance to fully mature. You can get started a few weeks earlier by starting your watermelon indoors.

Last Frost Date

On average the last frost when the weather gets warmer is on April 15 in Harrisburg. In the coldest months of winter you should expect an average low temperature of 0°F.

Remember that the actual date of last frost is just an average because it is based on the USDA zone info for Harrisburg and it is different every year. Since half of the time in Harrisburg you get surprised by a frost after April 15 be ready to protect your watermelon if you have a late frost.

USDA Zone Info for Harrisburg

Here is the info for USDA Zone 7a.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	0°F
Highest Expected Low	5°F

This means that on a really cold year, the coldest it will get is 0°F. On most years you should be prepared to experience lows near 5°F.

Plants to Grow in Harrisburg

You may be interested in your other planting guides for Harrisburg.